561542640 has 80 divisors (see below), whose sum is σ = 1843194528. Its totient is φ = 140935168.

The previous prime is 561542617. The next prime is 561542647. The reversal of 561542640 is 46245165.

561542640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561542647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64737 + ... + 72896.

Almost surely, 2^561542640 is an apocalyptic number.

It is an amenable number.

561542640 is an abundant number, since it is smaller than the sum of its proper divisors (1281651888).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

561542640 is a wasteful number, since it uses less digits than its factorization.

561542640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137666 (or 137660 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

The square root of 561542640 is about 23696.8909353105. The cubic root of 561542640 is about 825.0132302745.

The spelling of 561542640 in words is "five hundred sixty-one million, five hundred forty-two thousand, six hundred forty".